JPH0127352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cooling device of the type that uses water as a refrigerant and an aqueous solution of lithium bromide and/or its analogs as an absorbent. More specifically, the present invention relates to improvements in the absorption device of the cooling device.

It is essential to exclude non-condensable gases as completely as possible from the absorption devices of refrigeration systems based on the use of aqueous solutions of lithium bromide or its analogs as absorbent for water vapor. Such non-condensables are generally air and hydrogen, but may also be other gases such as ammonia. Removal of non-condensables is generally
This is achieved by forcing the non-condensables out of the bottom of the horizontal tube bundle of the absorber with water vapor. Compared to the efficiency of a non-scavenged chiller, the efficiency of a well-scavenged chiller is as much as about 70% higher, and the improvement can reach 100% if certain alcohols are used as additives.

As water vapor moves downward through the horizontal tube bundle, it condenses and its velocity decreases to about half of its initial velocity approximately in the middle of the tube bundle. At the lower end of the tube bundle there is an even lower velocity, which can lead to uneven flow, and sufficient velocity is achieved by non-uniform arrangement of the tube bundle.

Problems arise due to horizontal temperature gradients from one end of the tube to the other. This gradient depends on the number of water tube rows passing through the absorption device. Typically, a temperature rise of about 5° C. of the water occurs within the tube, and in a one tube arrangement this is the temperature gradient between the two ends of the tube. When multiple tube rows are used, this temperature gradient will be divided by the number of tube rows.

The colder section of the tube has a greater water vapor condensing capacity than the hotter section, and therefore there is a tendency for water vapor to pass through the hotter section of the tube bundle and move toward the cooler section.
Non-condensables are scavenged with this water vapor, thus
Their removal is impaired. If this process continues, significant buildup of non-condensables tends to occur, leading to a severe reduction in the efficiency of the cooling system. The aim of the invention is to eliminate the disadvantages resulting from horizontal temperature gradients in horizontal pipes passing through an absorption device.

The present invention provides an improved absorption system for refrigeration systems using water as the refrigerant and lithium bromide or the like as the absorbent. The absorption device is divided into a plurality of compartments, each compartment being provided with a drain line and a scavenging line.
This arrangement substantially improves the removal of non-condensable gases (air, hydrogen, etc.) and therefore the efficiency of the cooling system.

According to one preferred embodiment, tube support sheets arranged perpendicularly to the horizontal tubes form the partitions between the individual compartments. According to another preferred embodiment of the invention, the scavenging lines converge in a container maintained at a pressure lower than the pressure of the various compartments. Preferably, such a low pressure is achieved by spraying a suitable cooled solution of lithium bromide into the container, which is provided with baffle means separating the inlet tubes from each other. A relatively small amount of slightly cooled lithium bromide solution is sufficient to maintain this pressure below the pressure in the absorber compartment. Lithium bromide atomized in the chamber is returned to the absorption device, while non-condensable gases are removed from the top of the chamber and conveyed to the scavenging pump.

The temperature gradient between the inlet and outlet of the water into the horizontal pipes passing through the absorber is approximately 5°C, and the gradient along each pipe is equal to the number of horizontal pipes dividing such a 5°C temperature difference. Depends on. If a five-tube array is used, the temperature difference along each tube is only 1°C.
To eliminate the detrimental effects of this horizontal temperature gradient, the absorber is subdivided into compartments by partition walls perpendicular to the horizontal tube. The preferred length of each such compartment is about 75 to 150 cm, depending on the overall length of the absorber, which is generally 3 to 5 m long. Tube support sheets are preferably used as bulkheads, and these can extend downwardly to the bottom of the absorber or at least below the liquid level within the compartments to form a seal between the compartments. The pressures at the bottom of the various compartments vary due to temperature differences in the water flowing through the tube bundle.

In a typical 100 ton chiller, approximately 9 kg (20 lb) of water vapor enters the top of the absorber at a velocity of approximately 30.3 m (100 ft)/sec, which is approximately 15.2 m (50 ft) per second at the center of the tube bundle. /second.

A scavenging air line extends from each compartment to a common low pressure chamber;
A slightly cooled lithium bromide solution is sprayed into the chamber. Some cooling by about 1-2°C is sufficient and the amount of lithium bromide is generally about 13.7-36.4°C.
(3-8 gallons)/min. The upper part of the low pressure chamber is connected to an aspirator or a suitable vacuum pump. A jet aspirator of about 27800 cm ³ (1 cubic foot) per minute is sufficient, which conveys the vapor with the entrained noncondensables to a separate vessel, which is removed from the top of the separator, while the lithium bromide is recirculated from its bottom to the nozzle of the low pressure chamber.

Advantageously, a baffle plate is provided in the low-pressure chamber, the lower part of which is subdivided into a number of compartments depending on the number of compartments of the absorption device, and a scavenging line is provided in the lower part of the low-pressure vessel. It is growing. By slightly cooling the lithium bromide sprayed into this chamber, the chamber is maintained at a pressure lower than the pressure in either compartment of the absorber. Each compartment is equipped with a drain pipe for discharging the lithium bromide solution, which is sent via a heat exchanger to the generator of the cooling device. The non-condensate scavenging line is located in the lower part of the absorber, preferably lower than the lowest pipe in the compartment. The multi-compartment absorber arrangement provides very efficient removal of non-condensable gases (air, hydrogen, etc.) and greatly improves the efficiency of the cooling system.

By way of illustration, the invention will be described with reference to the accompanying drawings, which are not drawn to scale.

In the accompanying drawings, FIG. 1 is a cross-sectional view from the front of an absorption device that is a feature of the present invention; FIG. 2 is a schematic side view of a cooling device comprising an absorption device that is a feature of the present invention. 3 is a top view of the absorption device shown in FIG. 1; FIG.

As shown in FIGS. 1 to 3, the absorption device 11 is equipped with a two-line horizontal pipe 12 in which water is circulated, and the temperature gradient between the two ends 13 and 14 is approximately 5°C or approximately 2.5°C/tube. The absorption device is subdivided into two compartments, which are separated by a partition 17 which is also a tube support and which extends below the surface of the lithium bromide solution 18. Scavenging pipes 19 and 20 extend from each of the compartments 15 and 16, and a low pressure chamber 21, respectively.
The chamber is subdivided by internal baffles 22 and is connected to a separator jet 23 and a spray nozzle 24.

Drainage pipes 25, 26 from each of the compartments 15, 16
extend for the lithium bromide solution, respectively, to a pump 27 and a conduit 28, which leads to a heat exchanger 29,30.

Since it is subdivided into two compartments, the temperature gradient along the tube section within each compartment is only 1.25°C. When providing a larger number of compartments by using more than one internal partition, the temperature gradients in each compartment are correspondingly reduced, thus reducing the detrimental effects of horizontal temperature gradients.

The tube support sheet that makes up the compartment seal is
It can be used to form a seal at the bottom of the absorber. The pressure within the various compartments varies depending on the temperature at the bottom of each compartment. Lithium bromide solution drain tubes are arranged to provide a liquid seal in each compartment. Non-condensables are scavenged in low pressure chamber 21 from which lithium bromide is recycled, while non-condensables are removed from the top of the low pressure chamber via conduit 31.

As shown in FIG. 2, a cooling system of the type using water as a refrigerant and lithium bromide as a water vapor absorbent essentially consists of a combination of two vessels 32, 33 maintained at low pressure. , the container 32 surrounds the absorption device 11 and the evaporator 34, while the container 33 surrounds the generator 35 and the condensation device 36.

The refrigerant (water) enters the top of the evaporator 34 and is sprayed by a nozzle 37 onto the evaporator tube bundle. Heat from the liquid being cooled and also circulating through tubes 38 causes the refrigerant to evaporate. The water vapor travels to the absorber 11 where it is absorbed by a spray of lithium bromide through nozzle 39 and a dilute lithium bromide solution 40 collects at the bottom of the absorber. The evaporator is subdivided into two compartments 15, 16 (as shown in FIGS. 1 and 3) or into a number of such compartments. Some water vapor and non-condensable matter pass from the absorption device to the low pressure chamber 2 via the scavenging pipe line.
1 is removed. The chamber is equipped with a baffle plate 22 and slightly cooled lithium bromide is sprayed into the chamber through a nozzle 41, while the lithium bromide solution is passed through a conduit 42 to a pump 43 and into a conduit 44.
to heat exchanger 29 and from there to conduit 45
It is then discharged to the generator. After concentration, this lithium bromide solution is returned to the absorption device 11 via conduit 46, heat exchanger 29, while a small amount of lithium bromide is passed through heat exchanger 30, aspirator 23, conduit 47,
It is sent to the nozzle 41 via the separation device 48. Non-condensables are removed from the top of the low pressure chamber 21 via conduit 31 and aspirator 23 (operated by a lithium bromide flow).
It exits via a separating device 48 and exits at the top thereof via a conduit 49 to a storage container 50 . A portion of the lithium bromide solution coming from pump 43 via conduit 44 is circulated via conduit 51 through heat exchanger 30, where it is slightly cooled and transferred to low pressure chamber 2.
Together with the entrained non-condensables coming from 1 through conduit 31 , it passes through conduit 52 through aspirator 23 and is conveyed via conduit 47 to separation device 48 . The lithium bromide solution is conveyed via conduit 53 to spray nozzle 41 in low pressure chamber 21 .

By dividing the absorption device 11 into several compartments, the horizontal temperature gradient is correspondingly reduced, which prevents undesired horizontal movement of non-condensables,
The efficiency of their removal via the low pressure chamber 21 and the separation device 48 is improved.

It will be obvious that the foregoing description is for illustrative purposes only, and that many changes and modifications in the nature and arrangement of parts may be made without departing from the scope or spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view from the front of an absorption device that characterizes the cooling device of the present invention; FIG. 2 is a schematic side view of the cooling device of the present invention; FIG.
FIG. 2 is a top view of the absorption device shown in FIG. 1; 11... Absorption device, 12... 2-tube row type horizontal pipe,
17... Bulkhead, 19, 20... Scavenging pipe, 21...
...Low pressure chamber, 25, 26...Drain pipe line, 34...Evaporation device, 35...Generation device, 36...Condensation device,
48... Separation device.

Claims (1)

[Scope of Claims] 1. In an absorption type cooling device comprising an absorption device, an evaporation device, a condensation device, and a generation device, and using water as a refrigerant and an aqueous lithium bromide solution as an absorbent, penetrating the inside of the absorption device, An absorption device vessel having at least one horizontal conduit mechanism serving as a conduit for water, the absorption device being subdivided into a plurality of separate compartments by a substantially vertical sealing mechanism with respect to the conduit mechanism. A cooling device comprising a container of the device and a scavenging pipe for removing non-condensable gas and a liquid removal mechanism arranged in each of the compartments. 2. The cooling device according to claim 1, wherein the seal mechanism prevents horizontal flow of water vapor and non-condensable gas. 3. The cooling device according to claim 1, wherein the scavenging pipe is connected to a chamber equipped with a mechanism for maintaining a pressure lower than that of any compartment. 4. The cooling device according to claim 3, wherein the chamber is equipped with a mechanism for spraying a cooled lithium bromide aqueous solution. 5. The cooling device according to claim 1, wherein the sealing mechanism forming the compartment is a tube support mechanism. 6. The cooling device according to claim 1, wherein the scavenging pipe is connected to a vacuum pump. 7. The cooling device according to claim 3, wherein the low pressure chamber is provided with a baffle plate that separates the inlets of the scavenging pipes from each other. 8. The cooling system of claim 4, wherein the spray mechanism sprays about 3 to 8 gallons per minute.